FAILED: patch "[PATCH] ocfs2: validate directory-index entry counts when reading" failed to apply to 6.12-stable tree

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x bc70726ddad53c7e9a9a85915bf2415b0d4f42f9
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026090340-backside-dangling-fd8e@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From bc70726ddad53c7e9a9a85915bf2415b0d4f42f9 Mon Sep 17 00:00:00 2001
From: Doruk Tan Ozturk <[email protected]>
Date: Mon, 13 Jul 2026 22:56:25 +0200
Subject: [PATCH] ocfs2: validate directory-index entry counts when reading
metadata

ocfs2_validate_dx_leaf() and ocfs2_validate_dx_root() check the ECC and signature of an indexed-directory block before it reaches higher-level callers, but neither validator bounds the ocfs2_dx_entry_list counts against the capacity of the block that holds them.

ocfs2_dx_dir_search() then walks

	for (i = 0; i < le16_to_cpu(entry_list->de_num_used); i++)
		dx_entry = &entry_list->de_entries[i];

over de_num_used entries with no bounds check. entry_list is either dx_leaf->dl_list (from ocfs2_read_dx_leaf) or, for an inline root, dx_root->dr_entries. A crafted on-disk image can set de_num_used (and de_count, which is the __counted_by_le() bound of de_entries) to 0xffff and make the walk read far past the end of the 4KB metadata block, giving a slab out-of-bounds read reachable from any path lookup, stat() or open() on an indexed directory once the image is mounted.

Commit 775c17386a6f ("ocfs2: validate dx_root extent list fields during block read") already bounds dr_list for the non-inline dx_root, but left the inline dr_entries path and the dx_leaf dl_list unchecked. Add the same read-time validation for both entry lists: de_count must equal the capacity of the block (ocfs2_dx_entries_per_leaf()/per_root()) and de_num_used must not exceed de_count, rejecting corrupted metadata with -EFSCORRUPTED before ocfs2_dx_dir_search() can walk an out-of-range entry array.

de_count is always written as exactly the block capacity when a leaf or inline root is formatted, so the equality check does not reject any valid image.

Found by 0sec automated security-research tooling (https://0sec.ai).

index 047d1b486f4a..7e09a5a4d49e 100644
@@ -625,6 +625,28 @@ static int ocfs2_validate_dx_root(struct super_block *sb,
 					  le16_to_cpu(el->l_count));
 			goto bail;
 		}
+	} else {
+		struct ocfs2_dx_entry_list *dl_list = &dx_root->dr_entries;
+
+		if (le16_to_cpu(dl_list->de_count) !=
+		    ocfs2_dx_entries_per_root(sb)) {
+			ret = ocfs2_error(sb,
+					  "Dir Index Root # %llu has invalid de_count %u (expected %u)\n",
+					  (unsigned long long)le64_to_cpu(dx_root->dr_blkno),
+					  le16_to_cpu(dl_list->de_count),
+					  ocfs2_dx_entries_per_root(sb));
+			goto bail;
+		}
+
+		if (le16_to_cpu(dl_list->de_num_used) >
+		    le16_to_cpu(dl_list->de_count)) {
+			ret = ocfs2_error(sb,
+					  "Dir Index Root # %llu has invalid de_num_used %u (de_count %u)\n",
+					  (unsigned long long)le64_to_cpu(dx_root->dr_blkno),
+					  le16_to_cpu(dl_list->de_num_used),
+					  le16_to_cpu(dl_list->de_count));
+			goto bail;
+		}
 	}
 
 bail:

@@ -664,10 +686,25 @@ static int ocfs2_validate_dx_leaf(struct super_block *sb,
 		return ret;
 	}
 
-	if (!OCFS2_IS_VALID_DX_LEAF(dx_leaf)) {
-		ret = ocfs2_error(sb, "Dir Index Leaf has bad signature %.*s\n",
-				  7, dx_leaf->dl_signature);
-	}
+	if (!OCFS2_IS_VALID_DX_LEAF(dx_leaf))
+		return ocfs2_error(sb, "Dir Index Leaf has bad signature %.*s\n",
+				   7, dx_leaf->dl_signature);
+
+	if (le16_to_cpu(dx_leaf->dl_list.de_count) !=
+	    ocfs2_dx_entries_per_leaf(sb))
+		return ocfs2_error(sb,
+				   "Dir Index Leaf # %llu has invalid de_count %u (expected %u)\n",
+				   (unsigned long long)le64_to_cpu(dx_leaf->dl_blkno),
+				   le16_to_cpu(dx_leaf->dl_list.de_count),
+				   ocfs2_dx_entries_per_leaf(sb));
+
+	if (le16_to_cpu(dx_leaf->dl_list.de_num_used) >
+	    le16_to_cpu(dx_leaf->dl_list.de_count))
+		return ocfs2_error(sb,
+				   "Dir Index Leaf # %llu has invalid de_num_used %u (de_count %u)\n",
+				   (unsigned long long)le64_to_cpu(dx_leaf->dl_blkno),
+				   le16_to_cpu(dx_leaf->dl_list.de_num_used),
+				   le16_to_cpu(dx_leaf->dl_list.de_count));
 
 	return ret;
 }

From: Joseph Qi <[email protected]>

[ Upstream commit 775c17386a6fd695f999d4cda90e3931386570dd ]

Patch series "ocfs2: consolidate extent list validation into block read callbacks".

ocfs2 validates extent list fields (l_count, l_next_free_rec) at various points during extent tree traversal. This is fragile because each caller must remember to check for corrupted on-disk data before using it.

This series moves those checks into the block read validation callbacks (ocfs2_validate_dx_root and ocfs2_validate_extent_block), so corrupted fields are caught early at block read time. Redundant post-read checks are then removed.

This patch (of 4):

Move the extent list l_count validation from ocfs2_dx_dir_lookup_rec() into ocfs2_validate_dx_root(), so that corrupted on-disk fields are caught early at block read time rather than during directory lookups.

Additionally, add a l_next_free_rec <= l_count check to prevent out-of-bounds access when iterating over extent records.

Both checks are skipped for inline dx roots (OCFS2_DX_FLAG_INLINE), which use dr_entries instead of dr_list.

Stable-dep-of: bc70726ddad5 ("ocfs2: validate directory-index entry counts when reading metadata")

---
 fs/ocfs2/dir.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

index 119771c4a2ed3..6b9f6890c6090 100644
@@ -580,7 +580,7 @@ static int ocfs2_validate_dx_root(struct super_block *sb,
 		mlog(ML_ERROR,
 		     "Checksum failed for dir index root block %llu\n",
 		     (unsigned long long)bh->b_blocknr);
-		return ret;
+		goto bail;
 	}
 
 	if (!OCFS2_IS_VALID_DX_ROOT(dx_root)) {

@@ -588,8 +588,32 @@ static int ocfs2_validate_dx_root(struct super_block *sb,
 				  "Dir Index Root # %llu has bad signature %.*s\n",
 				  (unsigned long long)le64_to_cpu(dx_root->dr_blkno),
 				  7, dx_root->dr_signature);
+		goto bail;
+	}
+
+	if (!(dx_root->dr_flags & OCFS2_DX_FLAG_INLINE)) {
+		struct ocfs2_extent_list *el = &dx_root->dr_list;
+
+		if (le16_to_cpu(el->l_count) != ocfs2_extent_recs_per_dx_root(sb)) {
+			ret = ocfs2_error(sb,
+					  "Dir Index Root # %llu has invalid l_count %u (expected %u)\n",
+					  (unsigned long long)le64_to_cpu(dx_root->dr_blkno),
+					  le16_to_cpu(el->l_count),
+					  ocfs2_extent_recs_per_dx_root(sb));
+			goto bail;
+		}
+
+		if (le16_to_cpu(el->l_next_free_rec) > le16_to_cpu(el->l_count)) {
+			ret = ocfs2_error(sb,
+					  "Dir Index Root # %llu has invalid l_next_free_rec %u (l_count %u)\n",
+					  (unsigned long long)le64_to_cpu(dx_root->dr_blkno),
+					  le16_to_cpu(el->l_next_free_rec),
+					  le16_to_cpu(el->l_count));
+			goto bail;
+		}
 	}
 
+bail:
 	return ret;
 }
 

2.53.0

From: Doruk Tan Ozturk <[email protected]>

[ Upstream commit bc70726ddad53c7e9a9a85915bf2415b0d4f42f9 ]

ocfs2_validate_dx_leaf() and ocfs2_validate_dx_root() check the ECC and signature of an indexed-directory block before it reaches higher-level callers, but neither validator bounds the ocfs2_dx_entry_list counts against the capacity of the block that holds them.

ocfs2_dx_dir_search() then walks

	for (i = 0; i < le16_to_cpu(entry_list->de_num_used); i++)
		dx_entry = &entry_list->de_entries[i];

over de_num_used entries with no bounds check. entry_list is either dx_leaf->dl_list (from ocfs2_read_dx_leaf) or, for an inline root, dx_root->dr_entries. A crafted on-disk image can set de_num_used (and de_count, which is the __counted_by_le() bound of de_entries) to 0xffff and make the walk read far past the end of the 4KB metadata block, giving a slab out-of-bounds read reachable from any path lookup, stat() or open() on an indexed directory once the image is mounted.

Commit 775c17386a6f ("ocfs2: validate dx_root extent list fields during block read") already bounds dr_list for the non-inline dx_root, but left the inline dr_entries path and the dx_leaf dl_list unchecked. Add the same read-time validation for both entry lists: de_count must equal the capacity of the block (ocfs2_dx_entries_per_leaf()/per_root()) and de_num_used must not exceed de_count, rejecting corrupted metadata with -EFSCORRUPTED before ocfs2_dx_dir_search() can walk an out-of-range entry array.

de_count is always written as exactly the block capacity when a leaf or inline root is formatted, so the equality check does not reject any valid image.

Found by 0sec automated security-research tooling (https://0sec.ai).

---
 fs/ocfs2/dir.c | 45 +++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 41 insertions(+), 4 deletions(-)

index 6b9f6890c6090..dc1e379e58d50 100644
@@ -611,6 +611,28 @@ static int ocfs2_validate_dx_root(struct super_block *sb,
 					  le16_to_cpu(el->l_count));
 			goto bail;
 		}
+	} else {
+		struct ocfs2_dx_entry_list *dl_list = &dx_root->dr_entries;
+
+		if (le16_to_cpu(dl_list->de_count) !=
+		    ocfs2_dx_entries_per_root(sb)) {
+			ret = ocfs2_error(sb,
+					  "Dir Index Root # %llu has invalid de_count %u (expected %u)\n",
+					  (unsigned long long)le64_to_cpu(dx_root->dr_blkno),
+					  le16_to_cpu(dl_list->de_count),
+					  ocfs2_dx_entries_per_root(sb));
+			goto bail;
+		}
+
+		if (le16_to_cpu(dl_list->de_num_used) >
+		    le16_to_cpu(dl_list->de_count)) {
+			ret = ocfs2_error(sb,
+					  "Dir Index Root # %llu has invalid de_num_used %u (de_count %u)\n",
+					  (unsigned long long)le64_to_cpu(dx_root->dr_blkno),
+					  le16_to_cpu(dl_list->de_num_used),
+					  le16_to_cpu(dl_list->de_count));
+			goto bail;
+		}
 	}
 
 bail:

@@ -650,10 +672,25 @@ static int ocfs2_validate_dx_leaf(struct super_block *sb,
 		return ret;
 	}
 
-	if (!OCFS2_IS_VALID_DX_LEAF(dx_leaf)) {
-		ret = ocfs2_error(sb, "Dir Index Leaf has bad signature %.*s\n",
-				  7, dx_leaf->dl_signature);
-	}
+	if (!OCFS2_IS_VALID_DX_LEAF(dx_leaf))
+		return ocfs2_error(sb, "Dir Index Leaf has bad signature %.*s\n",
+				   7, dx_leaf->dl_signature);
+
+	if (le16_to_cpu(dx_leaf->dl_list.de_count) !=
+	    ocfs2_dx_entries_per_leaf(sb))
+		return ocfs2_error(sb,
+				   "Dir Index Leaf # %llu has invalid de_count %u (expected %u)\n",
+				   (unsigned long long)le64_to_cpu(dx_leaf->dl_blkno),
+				   le16_to_cpu(dx_leaf->dl_list.de_count),
+				   ocfs2_dx_entries_per_leaf(sb));
+
+	if (le16_to_cpu(dx_leaf->dl_list.de_num_used) >
+	    le16_to_cpu(dx_leaf->dl_list.de_count))
+		return ocfs2_error(sb,
+				   "Dir Index Leaf # %llu has invalid de_num_used %u (de_count %u)\n",
+				   (unsigned long long)le64_to_cpu(dx_leaf->dl_blkno),
+				   le16_to_cpu(dx_leaf->dl_list.de_num_used),
+				   le16_to_cpu(dx_leaf->dl_list.de_count));
 
 	return ret;
 }

2.53.0